There are instances where it is desired to determine the composition of a reservoir fluid for reservoir management purposes, such as to determine gas to oil ratios, fluid shrinkage, and extended composition. These fluids typically exist or are produced at elevated pressures and temperatures. Although some offshore platforms maintain a small laboratory for determination of basic fluid properties, space on the platform may not permit the equipment necessary to analyze the fluid in detail. Therefore, a sample taken on an offshore platform may be transported to an onshore testing facility. In some cases, it is not practical to maintain the voluminous analysis equipment at remote sampling sites, such as deep water offshore platforms, remote locations, underdeveloped countries, and rural areas. Depending on the location of the offshore platform or rural onshore sampling site, the sample may travel hundreds or thousands of miles to reach the testing facility. This travel can introduce a considerable lag between the time the sample is taken and the time the analysis is performed. This time lag discourages frequent testing and can reduce or sometimes eliminate retesting. The travel increases the likelihood that the sample will become compromised and/or contaminated, and introduces additional expenses related to travel and time into the costs of analysis. If a sample is contaminated or fouled during collection, transport, or otherwise, the contamination or fouling may not be discovered until the sample has traveled the many miles to reach the centralized testing facility. In such cases, when possible, another sample is then taken and transported to the centralized testing facility.
In some cases, the headspace vapor from a liquid, rather than the liquid itself, may be analyzed in a laboratory on an offshore platform. While this approach allows analysis at the site, the analysis may provide less information than desirable. Furthermore, when analysis of reservoir fluids includes flash vaporization, a separate apparatus may be required to flash the sample and collect the liquid and vapor phases, in which case the liquid and vapor phases are typically transferred to another apparatus for compositional analysis.